What we learned from 2012's West Nile virus outbreak

There have been over two dozen human cases of West Nile virus reported this season, but those numbers pale in comparison to what we were seeing at this point last year.

A new study takes a look at the 2012 outbreak, giving researchers important clues for prevention.

After five years of relatively mild mosquito activity, 2012 struck the nation hard with more than 5,000 reported West Nile virus cases and nearly 300 deaths. Louisiana saw right at 400 cases, including 21 deaths.

But it was Dallas County in Texas topping the list. Dallas County Judge Clay Jenkins said, "They refer to our area as an epidemic."

Researchers have pored over data collected in Dallas last summer to look for patterns that could predict future outbreaks. One thing they found is winter weather plays a large role in the summer mosquito population. Dr. Kristy Murray with Baylor College of Medicine said, "If you don't have a good freeze it's going to, of course, set you up for more mosquitoes later."

Keeping track of West Nile virus in mosquitoes can predict what is likely to be transmitted to humans. If there are lots of infected mosquitoes, there will be more human cases. Experts suggest spraying for the bugs sooner rather than later.

The risk from the insecticide was found to be low. "They showed that there was no increase in reported asthma cases or respiratory disease or anything like that," said Dr. Murray.

Contrary to popular belief, the rain we have seen this spring and summer could be helping by washing out mosquito breeding grounds. "It's really the nice rain that helps to flush those areas out and keep us free from mosquitoes," said Dr. Murray.

The key is making sure rain water does not collect in bird baths or flower pots where mosquitoes can multiply.

West Nile virus surveillance in Lafayette Parish shows an outbreak of the mosquito-borne disease. Officials confirmed that from dead birds, sentinel chickens and mosquito pools.

In Livingston Parish this week, a horse had to be euthanized after testing positive for both West Nile virus and Eastern Equine Encephalitis.